The difference in the mechanism of synthesis of yttrium-aluminum garnet Y 3 Al 5 O 12 (YAG) from a mixture of double yttrium and ammonium carbonate NH 4 Y (CO 3 ) 2 & middot; H 2 O with aluminum and ammonium hydroxycarbonate NH 4 AlCO 3 (OH) 2 and mixtures of hydrated yttrium and aluminum oxides. Calcining a mixture of hydrated oxides leads to the formation of both Y 3 Al 5 O 12 and impurity phases Y 4 Al 2 O 9 and YAlO 3 , while after calcining the mixture of carbonates, a monophase YAG is formed. The difference in the mechanism of YAG synthesis is presumably due to the difference in particle sizes formed after calcination of carbonates and hydrated oxides.
The results of experimental studies on the manufacture of prototypes of the elements of the lining of the flame tube of the combustion chamber from a ceramic composite material are presented, the structure and physical and mechanical properties of prototype samples are investigated, high-temperature bench tests of prototypes are carried out as part of an experimental structurally similar sample of the flame tube.
Various designs of molten glass granulators used in the production of glass containers and other glass products are considered. The main advantages and disadvantages of such equipment installed in the lines of utilization and recycling of cullet are stated.
The effect of modifying oxides Nb 2 O 5 , BaO, Ga 2 O 3 , TiO 2 < / sub> on the glass-forming ability, thermal, physical and optical properties of glasses of the four-component system La 2 O 3 & # 8211; Al 2 O 3 & # 8211; B 2 O 3 & # 8211; SiO 2 (LABS). It was found that when modifying the LABS system, it is possible to achieve high values ??of the refractive index (n D = 1.81) in combination with low crystallization ability and the possibility of obtaining optically uniform glass castings up to 150 mm in size. The variety of coordination states of modifier cations determines their complex effect on the properties of glasses and the appearance of non-monotonic concentration dependences of properties. Synthesis of multicomponent glass in a 300 ml crucible using optical glass-making methods confirms the promising nature of this composition for its implementation on an industrial scale.
A method for obtaining high-purity tungsten (VI) oxide based on two-stage sublimation purification has been developed. An impurity analysis of commercial preparations of tungsten (VI) oxide by inductively coupled plasma mass spectrometry was carried out. KGW crystals were obtained, grown using commercial reagents and tungsten (VI) oxide with a chemical purity of 99.999 & # 37; by mass. A comparative analysis of crystals grown from various initial tungsten oxides has been carried out. It is shown that the developed high-purity tungsten (VI) oxide does not reduce the chemical purity of the grown KGW crystals and is a promising raw material for the technology of glass-ceramic optical materials based on tungstates.
Transparent glass-crystalline materials co-activated with Eu 3+ / Gd 3+ were obtained by heat treatment of the initial lead fluoroborate glasses. It was found that the ions of rare-earth elements in the obtained transparent samples are located in nanoparticles of cubic crystals of lead fluoride, distributed in the bulk of the glass. It was shown that Eu 3+ ions are in a highly symmetric local environment and that the introduction of the second activator leads to an increase in the fraction of the nanocrystalline phase
The effect of diopside on the sintering temperature, structure and properties of low-temperature electrical porcelain has been investigated. In the porcelain mass, 12.5 & # 37; by weight of diopside concentrate, which is 10 & # 37; diopside CaMgSi 2 O 6 , excluding quartz (7.2 & # 37;) and reducing the
content of clay components by 5.3 & # 37 ;. Decrease in firing temperature
by 100 & # 176; С & ndash; up to 1220 & # 176; C and an increase in bending strength by 30 & # 37; up to 73 MPa due to reaction sintering during the interaction of diopside with decomposition products of clay components with the formation of anorthite and cordierite
The features of laser drilling of composite highly porous ceramics consisting of aluminosilicates, glass and a small addition of polystyrene (EPS) are studied experimentally. It was found that the formation of a liquid phase can contribute to the strengthening of ceramics. A list of factors determining the dynamics of hole formation is proposed. These include not only the previously known processes of heating, melting, ablation, and ejection for metals and dense ceramics, but also a number of others: boiling of the component of the mixture with the lowest temperature of thermal decomposition and its departure from the affected zone; melt less volatile component; sealing of ceramics adjacent to the walls; glass transition of the liquid phase upon cooling after irradiation. These effects depend on the density of the composite, as well as on the viscosity of the liquefied material.
A comprehensive study of various types of aluminum-containing raw materials and their influence on glass formation processes during the melting of borosilicate glasses for type E fiber has been carried out. up to 16.30 & # 37;
Investigated the chemical and mineralogical characteristics of alumina-containing waste & # 8211; catalysts of the gas processing industry and their use in the design of charge compositions of high-alumina ceramic grinding bodies. It has been established that this waste is a valuable nonmetallic ceramic raw material and the samples obtained on its basis belong to mullite materials for ceramic grinding bodies.
